1. Field of the Invention
The present invention relates to a footrest unit for a passenger seat in such as aircrafts, vessels and vehicles.
2. Description of the Related Art
An embodiment of a passenger seat having a conventional footrest unit, which is installed in a cabin of an aircraft, will be described with reference to FIGS. 6 and 7. In a seat 1, as shown in FIG. 6, a seat back 3 is rotatable mounted at a rear end of a seat cushion 2, a leg rest 4 is rotatably mounted at a front end thereof, and a footrest 5 is mounted on the leg rest 4 in such a manner that it can be extended and retracted.
The seat back 3, the leg rest 4, and the footrest 5 are adjusted by actuators (not shown) such as electric motors, and a passenger who is seated at the seat 1 operates a switch (not shown) by hand; thus, the angle of the seat back 3 can freely be adjusted between an upright position (refer to the solid lines in FIG. 6) at which the seat back 3 is almost perpendicular to the seat cushion 2 and an almost horizontal position (refer to the chain double-dashed lines A in FIG. 6), and the angle of the leg rest 4 can freely be adjusted between a housed position (refer to the chain double-dashed line B in FIG. 6) at which it is directed vertically downward and an almost horizontal position (refer to the chain double-dashed line C in FIG. 6). Also, the footrest 5 can freely be positioned between a retracted position (refer to the chain double-dashed line B in FIG. 6), at which the footrest 5 is housed in the leg rest 4, and an extended position (refer to the chain double-dashed line C in FIG. 6) at which it is fully extended.
Accordingly, the seat back 3 and the leg rest 4 can be moved to the horizontal position and the footrest 5 can be extended to the extended position; thus, the seat 1 can be used as a bed (refer to the chain double-dashed lines A and C in FIG. 6).
However, in the seat 1 shown in FIG. 6, when the leg rest 4 is moved to the housed position from a state in which the footrest 5 is at the extended position, or when the footrest 5 is extended from a state in which the leg rest 4 is at the housed position, it is necessary that the end of the foot rest 5 does not interfere with the floor 6.
Accordingly, in the conventional art, when the footrest 5 is moved in relation with an angular position (or the operation time) of the leg rest 4 to move the leg rest 4 from the horizontal position to the housed position, the footrest 5 is automatically moved backward when the leg rest 4 is rotated downward to a specified angle, and when the footrest 5 is extended from the leg rest 4 when it is at the housed position, the footrest 5 is extended after the leg rest 4 is rotated upward to a specified position.
However, the conventional footrest unit of the seat 1 has the following problems: As shown in FIG. 7, for example, when an obstacle 7 such as a baggage of a passenger is placed on the floor 6 below the footrest 5 which is at the extended position, when the leg rest 4 is rotated to the housed position, the end of the footrest 5 comes into contact with the obstacle 7 before the leg rest 4 reaches the specified angular position at which the footrest 5 is to be moved backward. There is, therefore, the risk that the obstacle or the seat 1 may be damaged as a result of the excess load applied thereto.
The present invention is made in the light of the above problems. Accordingly, it is an object of the present invention to provide a footrest unit for a passenger seat in which the interference of the movement of a footrest by an obstacle can be avoided during the operation of a leg rest or the footrest.
In order to achieve the above object, according to the present invention, a footrest unit of a passenger seat comprises: a leg rest which is rotatably mounted at a front end of a seat cushion; a footrest which is mounted on the leg rest in such a manner that it can be extended and retracted; actuators which can adjust the angle of the leg rest and the position of the footrest; and a non-contact proximity sensor provided at the end of the footrest, wherein the footrest is moved backward when the proximity sensor detects that the footrest is approaching an obstacle during the operation of the leg rest or the footrest.
In such an arrangement, when the proximity sensor detects the presence of an obstacle during the operation of the leg rest or the footrest, the leg rest is moved backward to avoid contact with the obstacle.
In the footrest unit of a passenger seat according to the present invention, preferably, when the proximity sensor detects that the footrest is approaching an obstacle, the downward rotation of the leg rest is stopped.
In such an arrangement, when the proximity sensor detects the presence of an obstacle, the downward rotation of the leg rest is stopped so that the footrest does not approach the obstacle.
In the footrest unit of a passenger seat according to the present invention, preferably, the leg rest can be rotated between an almost horizontal position and a housed position directed almost vertically downward.
In such a construction, the leg rest and the footrest can be arbitrarily positioned between the horizontal position and the housed position.
In the footrest unit of a passenger seat according to the present invention, preferably, the proximity sensor is either an optical proximity sensor or a sonic proximity sensor.
In such an arrangement, approach to the obstacle can be detected based on the change in the output voltage or the like from the optical proximity sensor or the sonic proximity sensor.